The present invention relates to microfluidic devices, and, more particularly, to modular microfluidic systems.
There has been a growing interest in the manufacture and use of microfluidic systems for chemical and biochemical manufacturing processes and the acquisition of chemical and biological information. In particular, microfluidic systems allow complicated biochemical reactions to be carried out using very small volumes of liquid. These miniaturized systems increase the response time of the reactions, minimize sample volume, and lower reagent cost.
Traditionally, microfluidic devices and components have been constructed in a planar fashion using photolithography to define channels on a silicon or glass substrate followed by etching techniques to remove material from the substrate to form channels. More recently, a number of methods have been developed that allow microfluidic devices to be constructed from plastic, silicone or other polymeric materials. In addition to the use of traditional injection cavity molding, the wide variety of molding steps or methods (generally involving the construction of a negative mold and then inserting material into or over the mold) that have been developed for constructing microfluidic devices include: fabricating molds with silicon wafers (e.g., Duffy, et al., Analytical Chemistry (1998) 70:4974-4984 and McCormick, et al., Analytical Chemistry (1997) 69:2626-2630); building components using a LIGA technique (e.g., Schomburg, et al., Journal of Micromechanical Microengineering (1994) 4:186-191) as commercialized by MicroParts (Dortmund, Germany); and combining LIGA fabrication steps with hot-embossing techniques, as performed by Jenoptik (Jena, Germany). Imprinting methods for producing microfluidic devices in PMMA have also been demonstrated (e.g., Martynova, et al., Analytical Chemistry (1997) 69:4783-4789). Still further methods for constructing other types of microfluidic devices have been provided, by the same applicant herein, in two published WIPO PCT patent applications, Nos. PCT/US00/27313 (WO 01/25137) and PCT/US00/27366 (WO 01/25138). Such methods include construction of microfluidic devices using circuit board and sandwiched stencil fabrication methods.
U.S. Pat. No. 6,086,740 to Kennedy, entitled xe2x80x9cMultiplexed Microfluidic Devices and Systems,xe2x80x9d (the xe2x80x9cKennedy Patentxe2x80x9d) discloses a xe2x80x98multiplexedxe2x80x99 microfluidic system for performing multiple fluidic operations in parallel. Multiple microfluidic modules are permanently connected a substrate, with each module sharing a common or connected input element. A single sample can be injected into all of the modules from a common port to perform multiple parallel analyses. Devices constructed according to the Kennedy patent, however, suffer from limited utility. For example, such devices lack fluidic connections between modules to perform sequential operations on a particular fluid with different modules. Further, no provisions are made in such devices to permit modules to be reconfigured, as may be desirable for experimental use or for optimizing fluid manipulation processes. Additionally, microstructures in devices constructed according to the Kennedy patent are constructed with surface micromachining techniques, which are time-consuming, capital-intensive, and not well-suited for generating devices in both low and high volumes.
Thus, there exist several different types of microfluidic devices that may be manufactured according to several different techniques. Despite the desirability of interconnecting or integrating such devices, however, to date no simple interconnection or integration methods or devices have been available. For example, a preparation system may be constructed using silicon fabrication technology while a sorting device might be constructed using a silicone replication technique (see, Fu, et al., Nature Biotechnology (199) 17:1109-1111). Though it would be desirable to combine such preparation and fabrication devices in a single integrated device, it would be difficult, if not impossible, to accomplish.
Moreover, discrete microfluidic components that perform specialized functions are often constructed. It would be desirable to quickly integrate such components into a complete system. For example, a silicon-based microfluidic sample preparation component can be constructed. A microfluidic detection component could also be separately constructed. To make a completed device, the developer must typically go back to the development stage and develop processing techniques and steps that allow a single integrated device to be developed.
Another issue in the development of microfluidic systems is the manner in which fluids and samples are introduced into and removed from a microfluidic device or system. It would be desirable to provide interface means that would permit fluids to be quickly and simply introduced or removed from such devices, and particularly for such an interface to be compatible with various types of microfluidic devices.
A need exists for a device or method for connecting together different types of microfluidic devices, such as may have been manufactured using different techniques. A further need exists for integrating discrete microfluidic components into a complete system. A still further need exists for aiding in the introduction and removal of fluids to and from microfluidic devices or systems.
A need also exists to provide a microfluidic system capable of fluidically connecting various modules to perform a sequence of operations on a fluid. Further utility could be gained if such a system were reconfigurable.
In a first separate aspect of the invention, a modular microfluidic system for performing a sequence of operations includes multiple microfluidic modules. Each module is capable of performing at least one operation in the sequence of operations, and the modules are fluidically coupled to perform the operation.
In another separate aspect of the invention, a modular microfluidic system for performing a sequence of operations on a fluid includes multiple microfluidic modules each fabricated with at least one stencil layer having a microfluidic structure defined through the entire thickness of the stencil layer. Each module is capable of performing at least one operation of the sequence of operations. The system further includes a microfluidic coupling device fabricated with at least one stencil layer having a microfluidic structure defined through the entire thickness of the stencil layer. The modules are fluidically coupled to perform the sequence of operations.
In another separate aspect of the invention, a method for performing a selected sequence of operations on a fluid includes the steps of identifying the operations of a sequence of operations, providing multiple microfluidic modules each capable of performing at least one operation of the sequence, fluidically coupling the modules to enable the sequence of operations to be performed, and providing at least one fluid to a module.
In another separate aspect of the invention, any of the foregoing aspects may be combined for additional advantage.
These and other aspects and advantages of the invention will become apparent to the skilled artisan upon review of the appended description, drawings, and claims.